---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 01/02/10: 21 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:51 AM - (Rino) 2. 06:52 AM - Issue with Garmin GTX 330 XPDR () 3. 09:11 AM - Re: AeroElectric-List Digest: 17 Msgs - 01/01/10 (speedy11@aol.com) 4. 09:13 AM - Questions about circuit protection () 5. 09:25 AM - Re: Questions about circuit protection (speedy11@aol.com) 6. 09:43 AM - Re: Noise filter ? (Robert L. Nuckolls, III) 7. 10:09 AM - Re: Questions about circuit protection. (Robert L. Nuckolls, III) 8. 10:11 AM - Re: THE VIRTUE OF SIMPLICITY (Ralph & Maria Finch) 9. 10:14 AM - Re: Re: AeroElectric-List Digest: 17 Msgs - 01/01/10 (Robert L. Nuckolls, III) 10. 11:09 AM - Re: Questions about circuit protection (Matthew Schumacher) 11. 11:12 AM - Re: Questions about circuit protection. (Matthew Schumacher) 12. 11:12 AM - Re: Adding an antenna to improve on the ground reception? (jim-bean@att.net) 13. 12:44 PM - Simplicity and circuit protection (Richard Girard) 14. 01:02 PM - Re: Questions about circuit protection. (Tim Andres) 15. 01:13 PM - Re: Simplicity and circuit protection (B Tomm) 16. 02:14 PM - Re: Simplicity and circuit protection (Richard Girard) 17. 05:19 PM - Re: Simplicity and circuit protection (mmayfield) 18. 07:10 PM - Z-14 Switch Combos (Perry, Phil) 19. 07:43 PM - Re: Simplicity and circuit protection (B Tomm) 20. 08:08 PM - Re: Re: Simplicity and circuit protection (Tim Olson) 21. 10:38 PM - Re: Questions about circuit protection (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:51:41 AM PST US From: "Rino" Subject: AeroElectric-List: Ton voyage s'est bien pass=E9? Tout =E9tait correct =E0 ton appart? Bises, Rita ________________________________ Message 2 _____________________________________ Time: 06:52:40 AM PST US From: Subject: AeroElectric-List: Issue with Garmin GTX 330 XPDR 1/2/2010 Hello Don Morrisey, You wrote: "I later discovered that each time I activate the Master SWitch the unit turns itself on even though I had left it powered off via the "Off" button on the unit. I went back over the wiring and nothing seems amiss??? Any idea why it would be doing this?" This very topic is currently being discussed on the aeroelectric list. Read the email exchanges below (last email is first). Also if you go to this web site, download the GTX327 installation manual and look at figure B4 on page 47 you will see the pins and notes that are being discussed. http://www.velocityxl.com/Downloads/GTX327Transponder_InstallationManual.pdf OC ========================================== Allen then wrote: Actually I meant 327 rather than 337. I looked at the installation manual pin out diagram and my Approach Systems engineer (Tim Hass) has pin 1 and pin 15 jumpered. The drawing calls pin 1 "Avionics Master on which may be the pin that I could unhook from power and make it work like we want. I emailed Tim Hass at Approach Systems to ask for clarification on this issue. I'll let you know what I find out. Allen ================================================= -----Original Message----- From: bakerocb@cox.net [mailto:bakerocb@cox.net] Sent: Friday, January 01, 2010 1:22 PM Subject: GTX337 ON or OFF? 1/1/2010 Hello Allen Fullmer, You wrote: "........skip.....I have also noticed that the GTX337 transponder cannot be set to remain off when power is supplied. It will remain in the standby position but, once again, when I am playing and fiddling around I just hate to see it go up and down unnecessarily. Haven't decided on a switch for it or not." I also can not program my GTX327 to remain OFF when power is applied or reapplied to the avionics buss.** But the GTX327 has some options on which pins electrical power can be supplied to. If you pick the correct pin(s) the box will remain OFF until you push the ON button on the face of the box. I suspect that the GTX337 may be built the same way. So if you desire, and have the capability, you could rewire your GTX337 so that it would remain OFF until you pushed the ON button on the face of the box. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." **PS: I suspect that the person who wired my panel set it up that way so that it would take a very deliberate OFF button action on my part in order to take off with the transponder OFF. I am with you, I'd like to have total ON - OFF control of the box with the buttons on the face of the box. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." ============================================== Time: 05:54:51 PM PST US From: Don Morrisey Subject: Avionics-List: Issue with Garmin GTX 330 XPDR Hello Listers I have just been finishing up my panel and one of the last things in was my transponder a Garmin GTX 330 . Very straightforward to install as I had a wiring harness made for it. Anyway got it in and it powered right up and does a self test etc. I later discovered that each time I activate the Ma ster SWitch=2C the unit turns itself on=2C even though I had left it powere d off via the "Off" button on the unit. I went back over the wiring and no thing seems amiss??? Any idea why it would be doing this? I have no issues with any of my other avionics that are connected to this wiring harness (SL40 and PMA 4000 Audi o Panel). Thanks. Don... www.donsbushcaddy.com Don Morrisey's Skunkworks ________________________________ Message 3 _____________________________________ Time: 09:11:33 AM PST US From: speedy11@aol.com Subject: AeroElectric-List: Re: AeroElectric-List Digest: 17 Msgs - 01/01/10 Jerry, All interesting information. But, your assumption is that you are the only safety conscious one on the forum and the rest of us are idiots. That simply is not the case. (If you doubt this comment, then refer to your comments below "I have a plan" and "overly complicated equipment and redundant backup systems, much of which you barely understand.") I wonder - why you think the rest of us are stupid? You said, "What concerns me is that all the emergency procedures required to take advantage of redundant systems must be committed to writing and to memory; then must be tested, practiced and periodically rehearsed." Why are you concerned? Do you fear that adding electric flaps instead of manual flaps adds complication? Using a flap example may seem like an invalid argument to you, but 40 years ago many were saying exactly what you are saying today about adding "too much complication" to the cockpit. Manual is better was the claim. In many ways it was. I prefer manual flaps even today. But the reality is that electric (or hydraulic - talk about complicated) flaps are the norm today. And appropriate emergency procedures are established for the "upgrade" to electricity. And suppose the electric (hydraulic) flaps don't work? You land anyway! What about electric starters? Lots of complications and emergency procedures added as a result of adding starters to airplanes. Propping is the way to go. Well ... except for that TIO-540. Well a TIO-540 is too complicated anyway - leave it off. Too many emergency procedures. I agree with you that any component added to the airframe complicates operations and emergencies somewhat - and adds weight. I do not agree with your admonishment of other builders that they are too ignorant to add such complication or redundancy. Other builders (myself excepted) undoubtedly have approximately the same level of "smarts" as you and they know to establish, verify, and practice emergency procedures for installed equipment. I hate it when "I know better than you" type people espouse their admonishments on the forum. We are building experimental aircraft. We are going to experiment. We may make good improvements for aviation. We will, by necessity, devise new emergency procedures to accommodate the improvements. We do plan for and practice the emergency procedures. And ... we are not stupid. BTW, have you ever started one of Ford's Model A's? Talk about complicated! I'll take the convenience of today's "complicated", computer-overloaded autos. Regards, Stan Sutterfield Do Not Archive Parts left out cost nothing and cause no service problems. Parts left out also can cause no emergencies or smoke in the cockpit. I believe that the first statement was attributed to GMs Charles Boss Kettering. Henry Ford was a great advocate of the value of simplicity too; whether it be in life, in work or in play. If our missions often involve flying IFR at night, then a very good case can be made for all the backups, added equipment and redundancy advocated in this forum. What concerns me is that all the emergency procedures required to take advantage of redundant systems must be committed to writing and to memory; then must be tested, practiced and periodically rehearsed. With the increased costs of flying, TRUE currency becomes even more elusive. During an emergency, pilots rarely have time to look in their POH for emergency procedures; you will not have time either. When the adrenalin and sweat is flowing and when fear and tunnel vision sets in is not the time to begin learning emergency procedures. What is your plan to counter smoke in the cockpit? I have a plan. The FAA is currently saying that you need one too. If 99% of your planned missions are day VFR, think twice or 3 times, before going overboard on adding overly complicated equipment and redundant backup systems, much of which you barely understand. And dont forget that your airplane will perform better with less weight. -------- Jerry King ________________________________ Message 4 _____________________________________ Time: 09:13:57 AM PST US From: Subject: AeroElectric-List: Questions about circuit protection 1/2/2010 Hello Matthew Schumacher, You wrote: "I think I will just get fuse blocks per your recommendation for the reasons you mention, but also because problems with a fuse can be remedied in the air quickly and easily." If you are thinking of replacing fuses in the air to trouble shoot and solve an electrical problem please think again. There are several disadvantages. Some are: 1) Your airplane's Operating Limitations (part of its airworthiness certificate) will require you to equip the aircraft in accordance with 14 CFR 91.205 if you fly at night or IFR. Paragraph 91.205 (c) (6) says: "One spare set of fuses, or three spare fuses of each kind required, that are accessible to the pilot in flight." This means that, by regulation, if you design your airplane so that you have access to those fuse blocks in flight then you must also have available to you all those spare fuses while in flight. Do you want to create that burden / nuisance / danger? 2) Trouble shooting an electrical system in flight by fumbling around to locate and then insert the appropriate fuse is not a good idea, particularly at night or IFR when you should be concentrating on flying the airplane. So fuse blocks are a good idea, but where you locate them has some operational and safety implications. Please read some more of Bob Nuckolls' philosophy regarding electrical problems / failures in flight. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." ======================================================== Time: 07:42:35 PM PST US From: Matthew Schumacher Subject: Re: AeroElectric-List: Questions about circuit protection. First, thank you very much for looking at my stuff Bob. I greatly appreciate it and have donated to keep this list going... ...................................... big skip ...................................... I know that fuses/breakers/fuselinks protect the wiring, what I was missing was the part about problems with one component spreading to others instead of being isolated. I think I will just get fuse blocks per your recommendation for the reasons you mention, but also because problems with a fuse can be remedied in the air quickly and easily. Thanks again, schu ________________________________ Message 5 _____________________________________ Time: 09:25:38 AM PST US From: speedy11@aol.com Subject: AeroElectric-List: Re: Questions about circuit protection Often times we get admonishments on this forum to not do something and our questions are never answered. While the admonishment is fine (and welcomed) when coming from someone so educated in electricity as Bob, getting the questions answered is the desire. Yes, you can bundle some of the lighting on a single breaker - realizing that the breaker and wires need to be sized accordingly for the load. Bob's advice is to consider using fuses. You can have a fuse for each light for a fraction of the cost in weight and money as the breaker. Personally, I chose breakers for my airplane. Personally I would not use a single breaker for the E-bus and omit breakers for individual devices on the bus. Again you would have to size the breaker for the entire load and wiring would have to match. In my opinion, not a logical approach. Bob's argument for fuses should again be considered. As far as fuselinks, I don't understand them either. I haven't studied them because I had no application for them. Regards, Stan Sutterfield Do not archive Can I group up some of the lighting on a single breaker? Also, what about using a breaker for the entire e-bus then omitting the breakers for the devices on the ebus? The lines will be real short and it eliminates the single point of failure (breaker.) Also, what about fuselinks? I understand them to be like a fuse that blows extremely slowly, but I'm not fully understanding when and where to use them. ________________________________ Message 6 _____________________________________ Time: 09:43:52 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Noise filter ? >However, my second radio is on my main bus. Should I stick a diode >and capacitor in its feed line after the fuse ? Or should I plan >instead to rectifiy any noise issues if I actually have them ? My >anti-collision lights will be LEDs, not strobes, but I tend to think >clean power is good power. Jeff, I wouldn't strike out to solve a "noise" problem that has yet to manifest itself. Many moons ago a builder called me one night to describe how he had shielded the majority of his system's wiring, put off the shelf filters on all potential victims and antagonists and was calling to ask, "is there anything I've overlooked?" I had to ask, "Gee, how does your noise problem manifest itself?" "Oh," he replies, "I'm still building. The airplane hasn't flown yet." This is a tip-of-the-bell-curve example of how NOT to approach the design and fabrication of a new system in an airplane. Keep in mind that the majority of antagonist/victim accessories are DESIGNED with their target application in mind. We consider DO-160 EMC and MIL-STD-704 power studies that teach us how to LIVE with a certain amount of noise on the bus while LIMITING how much noise we allow to be generated on the bus. I've seen dozens of products offered like the ubiquitous "surge protection" devices for computers . . . except these are intended to ward off evil spirits and slay dragons that are reputed to live on your airplane's power system. I think I spoke about extra-ordinary prophylactic noise mitigation in the chapter on noise in the 'Connection. Once you've shielded p-leads and crafted single point grounds, your probability of noise problems goes down to a tiny fraction of what's possible. The guy who called me about his noise mitigation program expended many hours, dollars and several pounds of empty weight on a useless activity. I can tell you that tens of thousands of strobe systems (and other potentially noisy appliances) have been successfully integrated into both TC and OBAM aircraft with no noise dragons to slay. Put the stuff all together first using ground rules established by decades of lessons-learned and let's tackle a noise problem later. It's likely that it won't show up. Bob . . . Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ ________________________________ Message 7 _____________________________________ Time: 10:09:55 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Questions about circuit protection. > > > > Why not simply add a switch in series with your > > e-bus normal feed path diode and label it > > "Avionics Master". Then ditch the avionics bus > > and run your avionics of concern along with > > endurance necessities from the e-bus. > >It is my understanding that the purpose of the e-bus is to be able to >open the battery contactor and instantly have the system load drop to >whatever is on the e-bus making it easier and quicker for the pilot to >shed unneeded load in the event of an alternator failure. No. The E-bus is where you power things that are part of your Plan-B for sustained flight battery only. YOU decide what the E-hours are. If you plan to maintain the battery such that E-power-hours is equal to or less than battery capacity, great. If some smaller performance value meets your design goals, great. But DECIDE what those design goals are and craft the system to match. >To that end I put only required avionics on the e-bus and avionics that >I don't absolutely need to have on an avionics bus thinking that this >was in line with the design goals of using an e-bus. Since you have subscribed to the ill-conceived notion of an 'avionics bus' then the simple solution is to COMBINED the functionality of the A-bus with the E-Bus and add the switch in series with the normal feedpath diode. You don't need to add a special bus to coddle radios that don't need coddling. >So my question is this: Given that simple is always >cheaper/lighter/more reliable, is it worth the weight/cost/complexity to >add a bus and a switch so that I can keep my avionics off during start, >and be able to instantly shed all non-critical loads? I thought it was, >but it seems like you disagree. As described above, the only increase in complexity to meet your design goals for an A-bus is make the E-bus double up in that capacity. Alternatively, you can abandon the legacy prophylactic for an A-bus and associated master switch. See: >Also, what are others doing here? Are they simply using the built in >power switch to turn stuff off at start (if the component has a built in >switch.) The avionics master switch was never really necessary for the reasons imagined at the time it was created. I remember. I was working as a tech writer at Cessna when the AV master was conceived. I wrote sections of maintenance manuals that spoke to the perceived hoards of hazard lurked upon the bus waiting to pounce on fragile radios. See: http://www.aeroelectric.com/articles/avmaster.pdf http://www.aeroelectric.com/articles/spike.pdf http://www.aeroelectric.com/articles/Philosophy/Whats_all_this_DO160_Stuff_Anyhow.pdf Today, we know better. There's no value to be added by dedicating a specially protected bus to power radios. >I know that fuses/breakers/fuselinks protect the wiring, what I was >missing was the part about problems with one component spreading to >others instead of being isolated. I think I will just get fuse blocks >per your recommendation for the reasons you mention, but also because >problems with a fuse can be remedied in the air quickly and easily. As Bob suggested in his earlier post, you might like to review the philosophy of breakers vs. fuses and the value of crafting a system where there are no designed in nuisance trips of fuses and no single accessory is "critical" . . . i.e. a failure tolerant system Fuse blocks can be tucked away out of sight, out of reach and out of mind. You need only ONE breaker and that only if you're using crowbar ov protection. Otherwise, it can ALL be out of reach fuses. Bob . . . ________________________________ Message 8 _____________________________________ Time: 10:11:54 AM PST US From: "Ralph & Maria Finch" Subject: RE: AeroElectric-List: THE VIRTUE OF SIMPLICITY To play the part of the loyal opposition: Yes, but. Do any of us really want to depend on one of the old cars for daily transportation? I have memories, almost all bad, of the old clunkers. I love my modern autos, turn the switch and they start and run. Oil changes at greatly increased intervals, hardly any "tune-ups" and such. Our lives would be simpler without building airplanes, dealing with computers, and so forth. But by definition those reading this are doing those things and other non-simple chores and hobbies. To airplanes. Day VFR implies no lights, even no radios. Stay out of Class B and no transponder required. My build is delayed considerably by adding lights and such but I want them. I'll also have an EFIS and autopilot because I think they nice and a good convenience. These are, after all, experimental. Experiment as you wish. Let's just be aware of all the costs of adding equipment. BTW, I'm flying an Aircoupe now. When my RV-9A is finished I don't think I'll notice a few extra pounds in comparison...and besides, most of us Americans could easily make up for added equipment weight by losing our spare tires ;-) Ralph Finch Davis, California RV-9A QB-SA -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of racerjerry Sent: Friday, January 01, 2010 12:21 PM THE VIRTUE OF SIMPLICITY __________ Information from ESET Smart Security, version of virus signature database 4735 (20100101) __________ The message was checked by ESET Smart Security. ________________________________ Message 9 _____________________________________ Time: 10:14:07 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: AeroElectric-List Digest: 17 Msgs - 01/01/10 At 11:07 AM 1/2/2010, you wrote: >Jerry, >All interesting information. >But, your assumption is that you are the only safety conscious one >on the forum and the rest of us are idiots. That simply is not the >case. (If you doubt this comment, then refer to your comments below >"I have a plan" and "overly complicated equipment and redundant >backup systems, much of which you barely understand.") >I wonder - why you think the rest of us are stupid? Gently my friend. Why do you take this as a personal attack? This is a forum for the exchange of ideas, crafting elegant design goals and the perfection of recipes for success. Please speak to ideas in the light of what I cited above. There's no reason for or value in pitching cabbages, tomatoes or rocks at each other. Bob . . . ________________________________ Message 10 ____________________________________ Time: 11:09:21 AM PST US From: Matthew Schumacher Subject: Re: AeroElectric-List: Questions about circuit protection bakerocb@cox.net wrote: > If you are thinking of replacing fuses in the air to trouble shoot and > solve an electrical problem please think again. There are several > disadvantages. Some are: > > 1) Your airplane's Operating Limitations (part of its airworthiness > certificate) will require you to equip the aircraft in accordance with > 14 CFR 91.205 if you fly at night or IFR. > > Paragraph 91.205 (c) (6) says: "One spare set of fuses, or three spare > fuses of each kind required, that are accessible to the pilot in flight." > > This means that, by regulation, if you design your airplane so that you > have access to those fuse blocks in flight then you must also have > available to you all those spare fuses while in flight. Do you want to > create that burden / nuisance / danger? Hold on, back the truck up. Are you saying that if I put the fuses under the panel where they aren't accessible then my airplane will still meet 14 CFR 91.205 (c) and that I won't need to carry spares? I would read "that are accessible to the pilot in flight" to mean that the fuse panel is accessible to the pilot, not the fusees since who cares if you can get to the fuses if you can't get to the panel. schu ________________________________ Message 11 ____________________________________ Time: 11:12:52 AM PST US From: Matthew Schumacher Subject: Re: AeroElectric-List: Questions about circuit protection. Robert L. Nuckolls, III wrote: > > Since you have subscribed to the ill-conceived notion > of an 'avionics bus' then the simple solution is > to COMBINED the functionality of the A-bus > with the E-Bus and add the switch in series with > the normal feedpath diode. You don't need to add > a special bus to coddle radios that don't need > coddling. > Thanks for taking the time to write all this out, I see where you are coming from now. schu ________________________________ Message 12 ____________________________________ Time: 11:12:52 AM PST US From: jim-bean@att.net Subject: Re: AeroElectric-List: Adding an antenna to improve on the ground reception? ________________________________ Message 13 ____________________________________ Time: 12:44:39 PM PST US Subject: AeroElectric-List: Simplicity and circuit protection From: Richard Girard The FAA has just released SAIB CE-10-11 "Electrical: Fire Hazard in Resetting Circuit Breakers" for operators of TC aircraft and transports, but the implications of it gives Bob's advice that much more teeth, IMHO. To summarize, the Feds are recommending that circuit breakers NOT be reset once they trip except under specific circumstances. The complete SAIB can be found here: https://www.faasafety.gov/files/notices/2009/Dec/SAIB_CE-10-11.pdf So, if you shouldn't reset them, what good are they? Rick Girard ________________________________ Message 14 ____________________________________ Time: 01:02:45 PM PST US From: "Tim Andres" Subject: RE: AeroElectric-List: Questions about circuit protection. Hi Bob; I think some of us may be dealing with conflicting information from two respected sources, yourself and in some cases the manufacturers. Garmin and Grand Rapids for example specify their equipment to be off during starter engagement, the Grand Rapids units do not have an on/off switch and as we have recently learned the GTX 327 may not really be off just because you selected off, and the use of a "A" bus is mentioned in the install manual. So in Matt's defense it may not be his following an "ill conceived notion" as you mentioned, but a desire to serve two masters. Tim Andres -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Saturday, January 02, 2010 10:09 AM Subject: Re: AeroElectric-List: Questions about circuit protection. > > > > Why not simply add a switch in series with your > > e-bus normal feed path diode and label it > > "Avionics Master". Then ditch the avionics bus > > and run your avionics of concern along with > > endurance necessities from the e-bus. > >It is my understanding that the purpose of the e-bus is to be able to >open the battery contactor and instantly have the system load drop to >whatever is on the e-bus making it easier and quicker for the pilot to >shed unneeded load in the event of an alternator failure. No. The E-bus is where you power things that are part of your Plan-B for sustained flight battery only. YOU decide what the E-hours are. If you plan to maintain the battery such that E-power-hours is equal to or less than battery capacity, great. If some smaller performance value meets your design goals, great. But DECIDE what those design goals are and craft the system to match. >To that end I put only required avionics on the e-bus and avionics that >I don't absolutely need to have on an avionics bus thinking that this >was in line with the design goals of using an e-bus. Since you have subscribed to the ill-conceived notion of an 'avionics bus' then the simple solution is to COMBINED the functionality of the A-bus with the E-Bus and add the switch in series with the normal feedpath diode. You don't need to add a special bus to coddle radios that don't need coddling. >So my question is this: Given that simple is always >cheaper/lighter/more reliable, is it worth the weight/cost/complexity to >add a bus and a switch so that I can keep my avionics off during start, >and be able to instantly shed all non-critical loads? I thought it was, >but it seems like you disagree. As described above, the only increase in complexity to meet your design goals for an A-bus is make the E-bus double up in that capacity. Alternatively, you can abandon the legacy prophylactic for an A-bus and associated master switch. See: >Also, what are others doing here? Are they simply using the built in >power switch to turn stuff off at start (if the component has a built in >switch.) The avionics master switch was never really necessary for the reasons imagined at the time it was created. I remember. I was working as a tech writer at Cessna when the AV master was conceived. I wrote sections of maintenance manuals that spoke to the perceived hoards of hazard lurked upon the bus waiting to pounce on fragile radios. See: http://www.aeroelectric.com/articles/avmaster.pdf http://www.aeroelectric.com/articles/spike.pdf http://www.aeroelectric.com/articles/Philosophy/Whats_all_this_DO160_Stuff_A nyhow.pdf Today, we know better. There's no value to be added by dedicating a specially protected bus to power radios. >I know that fuses/breakers/fuselinks protect the wiring, what I was >missing was the part about problems with one component spreading to >others instead of being isolated. I think I will just get fuse blocks >per your recommendation for the reasons you mention, but also because >problems with a fuse can be remedied in the air quickly and easily. As Bob suggested in his earlier post, you might like to review the philosophy of breakers vs. fuses and the value of crafting a system where there are no designed in nuisance trips of fuses and no single accessory is "critical" . . . i.e. a failure tolerant system Fuse blocks can be tucked away out of sight, out of reach and out of mind. You need only ONE breaker and that only if you're using crowbar ov protection. Otherwise, it can ALL be out of reach fuses. Bob . . . ________________________________ Message 15 ____________________________________ Time: 01:13:08 PM PST US From: "B Tomm" Subject: RE: AeroElectric-List: Simplicity and circuit protection "What good are they?" Easily reset (when back on the ground), easily pulled to disconnect during maintenance, or certain in-flight conditions. No fuses to buy and carry. Bevan _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Richard Girard Sent: Saturday, January 02, 2010 12:42 PM Subject: AeroElectric-List: Simplicity and circuit protection The FAA has just released SAIB CE-10-11 "Electrical: Fire Hazard in Resetting Circuit Breakers" for operators of TC aircraft and transports, but the implications of it gives Bob's advice that much more teeth, IMHO. To summarize, the Feds are recommending that circuit breakers NOT be reset once they trip except under specific circumstances. The complete SAIB can be found here: https://www.faasafety.gov/files/notices/2009/Dec/SAIB_CE-10-11.pdf So, if you shouldn't reset them, what good are they? Rick Girard ________________________________ Message 16 ____________________________________ Time: 02:14:50 PM PST US Subject: Re: AeroElectric-List: Simplicity and circuit protection From: Richard Girard Just my opinion but you can buy an awful lot of fuses for the price of a single C/B. As to being easily reset on the ground, that was exactly the condition that led to the crash that prompted the SAIB. Rick Girard On Sat, Jan 2, 2010 at 3:11 PM, B Tomm wrote: > "What good are they?" > > Easily reset (when back on the ground), easily pulled to disconnect during > maintenance, or certain in-flight conditions. No fuses to buy and carry. > > Bevan > > ------------------------------ > *From:* owner-aeroelectric-list-server@matronics.com [mailto: > owner-aeroelectric-list-server@matronics.com] *On Behalf Of *Richard > Girard > *Sent:* Saturday, January 02, 2010 12:42 PM > *To:* aeroelectric-list@matronics.com > *Subject:* AeroElectric-List: Simplicity and circuit protection > > The FAA has just released SAIB CE-10-11 "Electrical: Fire Hazard in > Resetting Circuit Breakers" for operators of TC aircraft and transports, > but the implications of it gives Bob's advice that much more teeth, IMHO. To > summarize, the Feds are recommending that circuit breakers NOT be reset once > they trip except under specific circumstances. The complete SAIB can be > found here: > > https://www.faasafety.gov/files/notices/2009/Dec/SAIB_CE-10-11.pdf > > So, if you shouldn't reset them, what good are they? > > Rick Girard > > * > > href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List > href="http://forums.matronics.com">http://forums.matronics.com > href="http://www.matronics.com/contribution">http://www.matronics.com/c* > > * > > * > > ________________________________ Message 17 ____________________________________ Time: 05:19:56 PM PST US Subject: AeroElectric-List: Re: Simplicity and circuit protection From: "mmayfield" I've always agreed that breakers can be useful, but not because they can be reset after they automatically trip. On both the military aircraft and passenger jets I've flown, the most useful thing about circuit breakers was always: 1) the ability to manually trip them when smoke starts pouring out of a system which is still powered (happened once to a colleague of mine). 2) the ability to pull then reset non-tripped breakers, usually under engineering guidance, to get a glitchy system to restart itself. For 25 years in my experience, resetting an already tripped breaker was discouraged or prohibited by SOPs in most circumstances, ground or flight, until maintenance action was carried out. I'm not sure why this concept should be a surprise to anyone. Mike Read this topic online here: http://forums.matronics.com/viewtopic.php?p=279823#279823 ________________________________ Message 18 ____________________________________ Time: 07:10:55 PM PST US Subject: AeroElectric-List: Z-14 Switch Combos From: "Perry, Phil" I'm getting a handle on Z-14 from an operational perspective and have a couple of questions about the switch combinations that could create issues. Obviously with the added complexity of managing two batteries, two alternators, and a cross feed can create some interesting combinations. Are there any combo's that we should be aware of that would create over voltage or any other scenarios of concern? In the event of a failure (for example Alt 2 failure), is there a specific order for shutting off the bad alt and then enabling the cross feed? Thanks, Phil ________________________________ Message 19 ____________________________________ Time: 07:43:53 PM PST US From: "B Tomm" Subject: RE: AeroElectric-List: Simplicity and circuit protection >From my recollection of the account I read somewhere on-line, that circuit breaker was reset (on the ground) without any troubleshooting to determine why it tripped and what, if any, damage has been caused. If this person reset it in the air, there would be no difference in this case, other than the fire would have started sooner. The point I did not make clear is that to "reset when on the ground", to me means to troubleshoot that circuit, not just to push it back in and see if a fire starts. Breakers and fuses do not trip for no reason other than an over current event. The questions are, what caused the over current event, did this event cause any damage, and depending on those answers, is it likely to trip again if nothing else is done but to reset it? Bevan _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Richard Girard Sent: Saturday, January 02, 2010 2:13 PM Subject: Re: AeroElectric-List: Simplicity and circuit protection Just my opinion but you can buy an awful lot of fuses for the price of a single C/B. As to being easily reset on the ground, that was exactly the condition that led to the crash that prompted the SAIB. Rick Girard On Sat, Jan 2, 2010 at 3:11 PM, B Tomm wrote: "What good are they?" Easily reset (when back on the ground), easily pulled to disconnect during maintenance, or certain in-flight conditions. No fuses to buy and carry. Bevan _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Richard Girard Sent: Saturday, January 02, 2010 12:42 PM Subject: AeroElectric-List: Simplicity and circuit protection The FAA has just released SAIB CE-10-11 "Electrical: Fire Hazard in Resetting Circuit Breakers" for operators of TC aircraft and transports, but the implications of it gives Bob's advice that much more teeth, IMHO. To summarize, the Feds are recommending that circuit breakers NOT be reset once they trip except under specific circumstances. The complete SAIB can be found here: https://www.faasafety.gov/files/notices/2009/Dec/SAIB_CE-10-11.pdf So, if you shouldn't reset them, what good are they? Rick Girard href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matro nics.com/Navigator?AeroElectric-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List tp://forums.matronics.com _blank">http://www.matronics.com/contribution ________________________________ Message 20 ____________________________________ Time: 08:08:35 PM PST US From: Tim Olson Subject: Re: AeroElectric-List: Re: Simplicity and circuit protection For some things that move control surfaces, I'd actually *insist* on pullable breakers....like electric trim, electric flaps, the Autopilot, and even electronic ignition. Those are things that some day you may want to find a way to pull power on...and would likely not even think about resetting them in most circumstances. Tim Olson - RV-10 N104CD do not archive mmayfield wrote: > > > I've always agreed that breakers can be useful, but not because they > can be reset after they automatically trip. > > On both the military aircraft and passenger jets I've flown, the most > useful thing about circuit breakers was always: > > 1) the ability to manually trip them when smoke starts pouring out of > a system which is still powered (happened once to a colleague of > mine). 2) the ability to pull then reset non-tripped breakers, > usually under engineering guidance, to get a glitchy system to > restart itself. > > For 25 years in my experience, resetting an already tripped breaker > was discouraged or prohibited by SOPs in most circumstances, ground > or flight, until maintenance action was carried out. I'm not sure why > this concept should be a surprise to anyone. > > Mike > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=279823#279823 > > ________________________________ Message 21 ____________________________________ Time: 10:38:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Questions about circuit protection > > >Hold on, back the truck up. Are you saying that if I put the fuses >under the panel where they aren't accessible then my airplane will still >meet 14 CFR 91.205 (c) and that I won't need to carry spares? > >I would read "that are accessible to the pilot in flight" to mean that >the fuse panel is accessible to the pilot, not the fusees since who >cares if you can get to the fuses if you can't get to the panel. First, 14 CFR 91.205 doesn't apply to an amateur built airplane. That's not to imply that the FARS don't have some things to be considered . . . but you have no obligation to consult these documents that apply to type certificated aircraft only. Further, 91.205 isn't the ONLY milestone at which your project is essentially "un-certifiable". But assume you adopt failure tolerance as a design goal. For every piece of equipment "critical" for the manner in which you plan to use the airplane, then that piece of equipment needs to be backed up with a plan-B. There are 100 times more failures in a piece of electronics that DOES NOT blow a fuse than there are failures that DO blow a fuse. If that piece of equipment is deemed critical, then having spare fuses for the circuit that supports that system is whistling in the dark. So assuming you have a back up for every POTENTIALLY critical system, then if follows that there are NO critical systems. Hence, whether or not you can reach breakers or fuses for any system is immaterial. 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